Adjusting Piezo Balance

[Kramer Ferrington III.]

I'm pretty fond of my ABG (Samick/Greg Bennett Regency) but if there's one fly in the ointment, it's that the pickup doesn't seem to be well balanced.

 

It sounds fine until you get to the G (it's 4 string bass) and then there's a noticeable drop in volume. It's livable, it's not like there's SILENCE, but it'd be cool if the G was louder.

 

Is there anything I can do? If it was a proper electric with proper electric pickups I'd grab a screwdriver and fix the problem but seeing as it's a piezo..? How the heck do you fix the balance?

 

Any suggestions?

[Paul K]

I had a piezo that I removed; on that one you couldn't individually adjust the output from each piezo. Carvins have individual trim pots for each string. I assume you opened up the back to see if trim pots are in the control cavity. Maybe a heavier gauge G-string would do the trick? Dunno, though. Just guessing.

[Max Valentino]

Balance is a probelm with piezo setups (usually cos it takes a bit of time and knowledge...something in short supply in most "factories"). First, not being too familair with that Samick model, does it have a bridge saddle that comes out of the bridge groove? Some budget ABGs feature a saddle with the piezo element "built in". In that case there is little you can do as those types of saddles are not made to opened and adjusted (you can...I have...but it is a pain and very time consuming)

If it is more like a traditional acoustic guitar bridge, then loosed the strings and remove them from the bridge. Remove the saddel and make sure the piezo strip element is sitting evenly in that groove. Sometimes just nudging this over can solve the prob...but usually not.

 

The bottom of the saddle must be completely flat. They are usually not coming from a factory. Theis is where it will conatact the piezo element. If it is not completely flat it will not contact well and then you have those volume issues.

Try sanding it flat...completely flat...with fairly fine wet/dry sandpaper.

It should also fit slip into the groove. It will rock slightly forward with string tension. This is often not a problem balance wise, though as the contact point, on a flat-bottomed saddle is even. I have known some to bevel the front edge slightly....seems to work for them. I have tried it and it has not worked for me.

 

Should this still not rectify the problem. You can apply a thin strip of copper or aluminum tape to the underside of the saddle (these tapes are used in pipe work and for stained glass work). Also, a tiny drop of super glue directly under where the strings pass (on the bottom of the saddle tho!!) can form a sort of suspension for the element. It can work both ways: lowering vol on strings which jump out, or raising vol on dimunuative strings.

 

Lastly, and I know it sounds weird, but it really works. Cut the saddle bone in half. Not exactly half...make the E and A string side just a tad longer. The put both halves back into the groove. This often cures any balance problem. It has something to do with dispensing the pressure evenly along the saddle...piezos read pressure changes as a voltage.

I say this is a last effort, as cutting the bone is something you should think about doing well before you do it. Finding new saddle bones foar an ABG can be problematic after you crack yours in this process....

 

Hope that helps

 

Max

[Gruuve]

I'm on my second bass with a piezo bridge now, so I'm not exactly an expert on 'em...but...I think in most cases there's a piezo sensor for each string. Check the control cavity for some sort of string balancing trim pots if you haven't already. It might be possible also that the saddle isn't positioned exactly right (depending on how the bridge is made). If the G-string has really low action, you might try raising it just a bit at the bridge saddle...that would put a little more pressure on the piezo sensor for that string.

 

Nothing else comes to mind right off...let us know what you find though.

 

Dave

 

[Max Valentino]

Very few ABGs use either indivdual piezos or indivdual trim controls. Most use a "strip" or ribbeon element (like those made by LR Baggs and Fishman). RMC uses indivdual sensors, with trim pots, ut most makers of ABGS opt for a more cost efficient version. some ovation models also have individual saddle mounted sensors. Citron uses special EMG sensors which are individual but two strings per sensor.

 

Chances are, it being a Samick, it uses a Fishman transducer which would be the little strip placed under the saddle bone.

 

Max

[Kramer Ferrington III.]

Wow! Thanks guys! I was about to *bump* this thread up the list, thinking nobody had seen it and... and here's all this useful info!

 

Thank you all very much!

 

Chances are, it being a Samick, it uses a Fishman transducer which would be the little strip placed under the saddle bone.

 

Max

 

Uhmm... no, I think it's meant to be a BelCat(?) It looks just

like the one here, if it wasn't for the missing "BelCat logo.

 

http://www.yhim.co.kr/data7/equalizer/eq_7545.htm

 

Oh well, here's the same pup without the logo. It looks exactly like mine. The logo's no great loss, it kind of grosses me out. It's meant to be a bass, not a formula one car.

 

http://www.highlystrung.co.uk/acatalog/eq7545r.jpg